Proceedings of UCLA Healthcare -VOLUME 21 (2017)-

CLINICAL VIGNETTE

The Clinical Spectrum of Crowned Dens Syndrome: An Analysis of Seven Cases

Ralph Yachoui, M.D.

Abstract

The crowned dens syndrome is an unusual manifestation of

calcium pyrophosphate dihydrate crystal deposition disease and

represents a rare cause of neck pain. We report seven cases of

crowned dens syndrome, assessing clinical and radiological

features, associated conditions, therapy, and outcome. The

acute presentation of crowned dens syndrome raised suspicion

for infectious meningitis and cranial giant cell arteritis in two

cases. Cervical cord compression was the initial presentation of

periodontoid calcium pyrophosphate deposition disease in two

other cases. A prior history or concurrent, self-limited,

peripheral arthritis was clinically or radiologically apparent.

Computed tomography scans performed better than magnetic

resonance imaging in assessing calcifications of the dens area.

We found a unique association with diffuse idiopathic squeletal

hyperostosis, Eagle’s syndrome, and Paget’s disease of bone.

Prompt initiation of therapy including isolated or combinations

of non-steroidal anti-inflammatory drugs, corticosteroids, and

colchicine yielded a dramatic response.

Introduction

Crowned dens syndrome (CDS) was first described in 1985 by

Bouvet et al1 and represents a rare cause of severe neck pain in

older adults. This radioclinical syndrome is defined by the

association of periodontoid calcifications in a crown-like

configuration and periodic attacks of febrile neck pain and

stiffness.2 This report illustrates the clinical and radiological

features of seven cases of patients with CDS.

Discussion

Crowned dens syndrome (CDS), also known as acute

pseudogout of the neck, is an unusual manifestation of calcium

pyrophosphate dihydrate crystal deposition disease (CPPD) and

is related to the microcrystalline deposition of calcium

pyrophosphate crystals in a periodontoid distribution.1 CDS

usually occurs in patients over 60 years of age and has a female

predominance.3

CDS is characterized by periodic attacks of acute, severe neck,

and shoulder girdle pain and stiffness mainly while attempting

to rotate the head from side to side.3,4 Fever, headaches, and

raised inflammatory markers are frequently present.2-4 As

illustrated in the cases we will present in this report, a prior

history or concurrent, self-limited, peripheral arthritis may be

clinically or radiologically apparent.5 CPPD deposition can be

precipitated by an underlying metabolic condition like

hyperparathyroidism. We found a unique association with

diffuse idiopathic squeletal hyperostosis, Eagle’s syndrome,

and Paget’s disease of bone.

The acute presentation of CDS frequently raises suspicion for

infectious meningitis, epidural abscess, polymyalgia

rheumatica, giant cell arteritis, and/or metastatic malignancy.5

A thorough investigation, such as we describe in cases 5 and 7,

is necessary to make the correct diagnosis of CPPD.

Cervical CPPD is common in patients with peripheral CPPD,

often remaining asymptomatic.6-8 In a retrospective study

conducted by Salaffi et al,6 in 25 of 49 patients (51%) affected

by peripheral CPPD, computed tomography (CT) scan of the

cervico-occipital junction showed periodontoid calcified

deposits. Only nine of the cervical CPPD cases had neck

symptoms.

CT scanning performs better than magnetic resonance imaging

(MRI) in assessing calcifications of the dens area and, therefore,

considered the gold standard for diagnosis.6 Plain radiograph is

notoriously insensitive in detecting periodontoid opacification.

CPPD crystal deposits in and around C1-C2 can lead to osseous

abnormalities of the odontoid process, such as subchondral

cysts, erosions, and even fractures of the odontoid.6,9

Cases 1 and 2 were particularly interesting, as cervicomedullary

compression was the initial presentation of periodontoid CPPD.

To date, few cases of cervical CPPD causing atlantoaxial

instability, spinal cord compression, and myelopathy have been

reported.10-12 Similar to our index patient, most lesions were

treated by surgical decompression via the transoral route with

good post-surgical outcomes.13

Treatment first involves non-steroidal anti-inflammatory drugs,

which are highly effective within days. Systemic

corticosteroids, C1-2 steroid injection, or colchicine have also

been used with good clinical efficacy.1,2,4,5,14

Case 1

A 64-year-old man was admitted to the intensive care unit for

respiratory failure and quadriparesis. He had a history of

thyroid cancer treated with surgical resection, currently on

thyroid replacement, newly-diagnosed primary

hyperparathyroidism, and diffuse idiopathic skeletal

hyperostosis. On examination, he could not lift all four

extremities against gravity. There was no clear sensory level.

MRI of the cervical spine revealed low signal intensity mass on

T2-weighted image posterior to the C2 vertebral body leading

to severe canal compromise and myelopathic signal changes

within the cord [Figure 1A-C]. On non-enhanced CT imaging,

the mass had amorphous mineralization compatible with CPPD

[Figure 1D].

The patient underwent C1 through 5 laminectomies with

posterior instrumented fusion. Four months after the initial

presentation, his quadriparesis completely resolved.

Case 2

An 84-year-old man was seen by neurosurgery for severe neck

pain and cord compression on imaging. He had been well until

2 years earlier, when he developed neck pain and stiffness that

was initially intermittent but became constant. His pain was

localized to the left side of the neck with radiation to the left

parietal area and left forehead. He denied numbness or

weakness in the arms or legs, swallowing or breathing

difficulties. He had a history of generalized osteoarthritis, and

prior C3-7 laminectomy. On examination, there was tenderness

on palpation of the cervical spine with limited range of motion

in all planes.

MRI scans showed a large nonenhancing soft tissue mass

involving the C1-2 articulation with a cystic component

extending into the canal on the left side, causing mild cord

compression. There was no high signal seen within the cervical

spinal cord at this level [Figure 2A-D]. A CT scan demonstrated

amorphous calcifications within the soft tissue mass and mild

erosive changes of the dens, most compatible with cervical

deposition of calcium pyrophosphate crystals [Figure 2E, F].

Bilateral hand and knee radiographs showed chondrocalcinosis

and findings typical of calcium pyrophosphate arthropathy.

Given the absence of signs and symptoms of a progressive

myelopathy, non-operative treatment with low-dose prednisone

and topical diclofenac was initiated. The neck pain and stiffness

significantly improved.

Case 3

A 71-year-old man was evaluated for a 5-year history of

episodic upper cervical pain and stiffness. He had a history of

documented crystal pseudogout affecting the wrists and knees.

Other medical problems included stage IV chronic kidney

disease, secondary hyperparathyroidism and coronary artery

disease. He had tenderness and restriction of neck movement,

especially on any attempt to rotate the head from side to side.

His erythrocyte sedimentation rate (ESR) was 90 mm/h, and C-

reactive protein was 12 mg/dL (range, 0.0-1.0 mg/dL).

Cervical MRI revealed soft tissue thickening at the C1-2 level

extending slightly within the spinal canal without compression

of the spinal cord [Figure 3A]. A subsequent CT showed a

pannus with crown-like mineralization surrounding and slightly

eroding the dens. On dual energy images, the calcification had

blue signal similar to the cortex of the skull base and cervical

spine, consistent with calcium pyrophosphate crystals [Figure

3B-D]. Skeletal radiographs revealed chondrocalcinosis at

bilateral hips, knees, wrists and pubic symphysis. Treatment

with prednisone 5 mg daily and colchicine 0.6 mg twice daily

was followed by rapid improvement in neck symptoms and

reduction in the frequency of flare-ups.

Case 4

A 54-year-old man was seen with diffuse chondrocalcinosis. He

had a history of a chronic arthropathy manifesting as mild joint

pain and stiffness of knees, wrists, metacarpophalangeal joints,

and shoulders. He reported intermittent neck pain associated

with marked stiffness. Physical examination elicited tenderness

throughout the posterior cervical spine and severe loss of neck

and shoulder movement.

Plain radiographs showed multilevel cervical spondylosis, and

1st through 3rd metacarpophalangeal predominant arthropathy

with chondrocalcinosis of knees, bilateral glenohumeral, and

acromioclavicular joints. Laboratory workup including ferritin

level, parathyroid hormone, calcium, magnesium, and alkaline

phosphatase was normal. A cervical CT revealed periodontoid

calcifications affecting the transverse ligament of the atlas in a

‘crown-like’ appearance, compatible with CPPD [Figure 4A,

B].

A trial of nonsteroidal anti-inflammatory drugs was

unsuccessful because of gastric intolerance. He was started on

short cycles of low-dose prednisone with satisfactory control of

his neck symptoms.

Case 5

A 92-year-old man presented to the emergency department with

complaints of severe headaches and neck pain for 5 days. Initial

clinical examination found cervical stiffness with Brudzinski’s

sign. Laboratory tests showed white blood cells 14 400/mm3,

ESR 71 mm/hr, and C-reactive protein 18 mg/dL. Infectious

meningitis was suspected; however, a lumbar puncture was

normal.

Skeletal radiographs revealed extensive chondocalcinosis of

shoulders, knees, and wrists. A cervical CT scan of C1/C2

allowed the diagnosis of crowned dens syndrome showing

small mineralization behind the odontoid process in addition to

subtle posterior longitudinal ligament mineralization at C2-C3

and C3-C4 [Figure 4C].

His headaches, neck pain, and stiffness dramatically improved

3 days later with low-dose prednisone and with normalization

of biological parameters in 14 days.

Case 6

An 86-year-old man was hospitalized with upper cervical

thoracic pain that had profoundly worsened over the last week.

The pain was severe, nonradicular, nonmyelopathic, and

unrelated to time of day, positioning, or activity. He had a

history of tophaceous gout, Paget’s disease of bone, generalized

osteoarthritis, and severe osteoporosis. Examination showed

greatly limited cervical extension and flexion, particularly

lateral rotation.

CT examination of the cervical spine revealed extensive

multilevel degenerative changes, ossification of the stylohyoid

ligament bilaterally, and chondrocalcinosis present at the C1-2

level compatible with CPPD [Figure 4D].

Treatment with prednisone 10 mg daily and low dose colchicine

resulted in rapid symptom improvement. The patient died 1

month later from unrelated cryoglobulinemic vasculitis.

Case 7

An 85-year-old woman developed intermittent right-sided

headache, which became daily after a couple of weeks. The

head pain was felt most intensely in the right temporal-occipital

area. There was no jaw or tongue claudication, visual

disturbances, diffuse myalgias, or constitutional symptoms. She

had a history of crystal-proven pseudogout of the ankle, C1

vertebral body ring fracture from a previous fall, osteoporosis,

and diabetes mellitus. The neurological and general

examinations were normal, except for a reduced range of

motion of the neck and slight tenderness over the right temporal

artery.

She was referred to a rheumatologist for suspicion of cranial

giant cell arteritis. Her ESR was 55 mm/h, and C-reactive

protein was normal. She received steroid therapy in anticipation

of the temporal biopsy. Giant cell arteritis was not confirmed

on histological examination of the right temporal artery.

A cervical CT showed atlantoaxial instability with widening of

the predental space, cranial settling with occipital condyles

essentially articulating with C2 lateral masses due to separate

C1 lateral masses as a consequence of the previous C1 fracture

and an extensive retrodental partially calcified soft tissue mass

leading to marked disintegration of dens and mild spinal canal

stenosis consistent with CPPD [Figure 4E-G]. The

neurosurgeon opted against surgical intervention because of

absence of neurological signs and cervical myelopathy.

The patient was prescribed colchicine 0.6 mg daily. After a

week, her headache improved. After 2 months, colchicine was

stopped as she was completely asymptomatic.

Conclusion

Clinicians should be aware of CDS as a significant cause of

acute febrile neck pain in older adults. Often asymptomatic,

CDS is likely under recognized, as many cases go undiagnosed.

The prompt initiation of therapy usually yields a dramatic

response. Long-term follow-up is necessary, as neck CPPD can

sometimes lead to cord compression with significant

neurological sequelae.

Table and Figures

Table 1.

Figure 1. Cervical spine MRI sagittal T2-weighted (A) and

axial T2-weighted images (B,C). Pannus with low T2-weighted

mineralization (arrows), compatible with CPPD, surrounds the

dens, extends within the spinal canal and causes severe central

canal stenosis and compression of the spinal cord. (D) Head CT

scan, axial image. Pannus with amorphous mineralization

(arrows), compatible with CPPD, surrounds the dens, extends

within the spinal canal, and causes severe central canal stenosis

and compression of the spinal cord.

Figure 2. Cervical spine MRI sagittal T1-weighted (A), sagittal

T2-weighted (B), axial T2-weighted (C) and T1 fat saturation

post contrast images (D). Nonenhancing pannus (double arrow)

with low T1 and T2-weighted mineralization (single arrows)

and a cystic component (dashed arrow), compatible with CPPD,

surrounds the dens, extends within the spinal canal and causes

severe central canal stenosis and compression of the spinal

cord. Cervical spine CT scan axial (E) and sagittal images (F).

Pannus with amorphous mineralization (black arrows),

compatible with CPPD, surrounds, and slightly erodes the dens

(yellow arrow), extends within the spinal canal and causes

severe central canal stenosis and compression of the spinal

cord.

Figure 3. Cervical spine MRI sagittal T2-weighted image. (A)

Pannus with low T2-weighted mineralization (arrow),

compatible with CPPD, surrounds the dens and slightly extends

within the spinal canal without compression of the spinal cord.

Cervical spine CT sagittal (B), dual energy sagittal (C), and

dual energy axial images (D). Pannus with amorphous

mineralization (arrows), compatible with CPPD, surrounds and

slightly erodes the dens (dashed arrow). On the dual energy

images (B,C), the CPPD is blue due to calcium, which matches

the same blue color as the adjacent bone.

Figure 4. Cervical spine CT sagittal (A) and axial with soft

tissue algorithm images (B). Mineralization surrounding the

dens (arrows), compatible with CPPD. Cervical CT axial (C) at

the C1/C2 level showing linear calcifications of the transverse

ligament of the atlas. Cervical spine CT sagittal (D). Pannus

with amorphous mineralization (arrow), compatible with

CPPD, surrounds the dens. CT cervical spine sagittal (E) shows

extensive soft tissue thickening surrounding the dens with

erosion secondary to CPPD. The pannus formation displaces

the cervicomedullary junction posteriorly; (F) shows extensive

erosion of the dens with adjacent osseous debris and

mineralization, compatible with CPPD. Marked diastasis of the

atlantodental interval and cranial settling are due to a chronic

C1 Jefferson fracture, which are not completely visualized on

this image. CT cervical spine axial image (G) shows

mineralization and pannus surrounding an eroded dens,

compatible with CPPD.

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Submitted May 30, 2017